The ignition circuit for two-stroke engines, in particular for two-stroke engines in handheld work apparatus, essentially includes a generator for generating the required ignition energy and an ignition circuit via which an Ignition spark is triggered at a spark plug at predetermined crankshaft angles. The spark plug together with the ignition coil, there the secondary winding of the ignition coil, forms a high voltage circuit which can also be referred to as a power circuit. If the ground connection of the power circuit is electrically interrupted by a defect, high voltage conditions, which can lead to damage to the ignition circuit, can occur.
In order to be able to perform an adaptation of the ignition timing to current operating parameters of the combustion engine, sensors, which, for example, capture and transmit the crankcase pressure or the crankcase temperature to the ignition circuit, are also provided in such ignition circuits.